Dilute Ammonia Pretreatment of Sorghum and Its Effectiveness on Enzyme Hydrolysis and Ethanol Fermentation Deepti A. Salvi & Giovanna M. Aita & Diana Robert & Victor Bazan Received: 22 May 2009 / Accepted: 10 February 2010 / Published online: 27 February 2010 # Springer Science+Business Media, LLC 2010 Abstract A new pretreatment technology using dilute ammonium hydroxide was evaluated for ethanol production on sorghum. Sorghum fibers, ammonia, and water at a ratio of 1:0.14:8 were heated to 160 °C and held for 1 h under 140–160 psi pressure. Approximately, 44% lignin and 35% hemicellulose were removed during the process. Hydrolysis of untreated and dilute ammonia pretreated fibers was carried out at 10% dry solids at an enzyme concentration of 60 FPU Spezyme CP and 64 CBU Novozyme 188/g glucan. Cellulose digestibility was higher (84%) for ammonia pretreated sorghum as compared to untreated sorghum (38%). Fermentations with Saccharomyces cerevisiae D 5 A resulted in 24 g ethanol /100 g dry biomass for dilute ammonia pretreated sorghum and 9 g ethanol /100 g dry biomass for untreated sorghum. Keywords Dilute ammonia pretreatment . Sorghum . Ethanol . Lignocellulosic . Biomass . Hydrolysis Introduction The definition of biomass refers to organic non-fossil material of biological origin constituting a renewable energy source [1]. Lignocellulose is a type of biomass and refers to any plant material produced by photosynthesis. Wood, sugarcane bagasse, sorghum, corn fibers, rice straw, wheat straw, barley straw, coconut husks and pineapple leaves are just a few examples [2, 3]. The major components of lignocellulosic biomass are cellulose, hemicellulose, and lignin. The facility to make fuels and or other value added products from lignocellulosics depends on the ability to separate and to breakdown each of these structures into their main components glucose, xylose and phenols; respectively. Appl Biochem Biotechnol (2010) 161:67–74 DOI 10.1007/s12010-010-8932-1 D. A. Salvi : G. M. Aita (*) : D. Robert : V. Bazan Audubon Sugar Institute, Louisiana State University Agricultural Center, 3845 Hwy 75 St., Gabriel, LA 70776, USA e-mail: gaita@agcenter.lsu.edu